Agriculture extensive sur brulis et dynamique de l’occupation des sols dans l’arrondissement de Nyanon (sanaga-maritime)

Abstract

This research explores the implications of extensive slash-and-burn farming on land use in the Nyanon subdivision which is occupied by a densely evergreen forest which competes with some minor savannah areas. The central issue is to determine the impacts of crop production on stand dynamics and biodiversity. The main research hypothesis is that extensive slash-and-burn farming is at the basis of forest and savannah loss as well as the reduction of their biodiversity. Within the same time span, some savannah swathes have witnessed an increase in woody covers. To carry out this work, significant literature research has been conducted and completed with other research methods such as direct observation during fieldwork, botanical and population surveys for primary source data collection. Using Cochran’s theorem, a sampling of 9 representative villages have been designed on a scale of 47 villages that make up the subdivision under investigation. For botanical surveys, an inventory of 03 forest plots has been done in the forest area. They include a mature forest, two fallow lands forest of twenty and nine years of one hectare surface area. Besides, two savannah plots of 400m2 have been identified, namely one in an unexploited area and the other in a three-year savannah fallow area. These different surveys enabled to have good knowledge of the floristic makeup for a better account of the stand dynamics of land occupation in relation with slash-and-burn farming. The findings reveal that the increase of this farming practice is the result of many ecological and human factors such as climate, vegetation, relief patterns, and mainly demographic pressure. It is worth mentioning that this practice is characterized by a number of factors ranging from clearing to fallowing. Following the stand dynamics undertook between 2007 and 2020, the study reveals that forest ecosystems have declined for the benefit of crops. However, the afforestation rate has slightly increased even though forest degradation has been extended altogether.